This project is designed to expand our knowledge of the chemistry of the glycoprotein hormones. Major objectives will be the determination of the amino acid sequence for rabbit LH, equine LH, and chicken LH. Although the amount of rabbit FSH and chicken FSH available will be somewhat more limited we will also undertake as much sequence determination as the material may allow. This research will allow across-class comparisions of structural features of the glycoproteins from mammalia and aves. This is of interest is connection with our recently proposed hypothesis for a determinant loop (residues 93-100) on the beta subunit of the glycoprotein hormones. For our bioassay characterizations of the preparations we will utilize radioligand assays and in vitro steroidogenesis assays, since these assays require less material and most of our preparations will be available in limited supply. To conserve material for the sequencing studies we will take advantage of whatever homologies to known glycoprotein hormone sequences are available. This should allow us to design the most conservative approach initially and probably reduce the hormone quantities required (to place overlaps, etc.) as the sequencing progresses. The material requirements will be further reduced by applying recently developed increases in sensitivity for sequence determination (35S-labeled reagents, solid-phase sequencing, improved PTH-amino acid detection and quantitation).